TB62737FUG(O,EL) Toshiba, TB62737FUG(O,EL) Datasheet - Page 6

• Manufacturer Part Number: TB62737FUG(O,EL)
• Description: IC LED DRIVR WHITE BCKLGT 6-SSOP
• Manufacturer: Toshiba
• Type: Backlight, White LEDr

Specifications of TB62737FUG(O,EL)

• Constant Current: Yes
• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 770kHz ~ 1.43MHz
• Voltage - Supply: 2.8 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: SC-74-6
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 20mA
• Internal Switch(s): Yes
• Efficiency: 87%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Other names: TB62737FUGTR

2) Input PWM signal to SHDN terminal
I
[Notice]
F
can be adjusted with PWM signal by inputting it to SHDN terminal.
<<Minimum ON-time of PWM signal input>>
<<PWM signal frequency>>
<<Constant number of external condenser>>
<<PWM input signal>>
<<Rush current in inputting>>
<<Current value in Control with PWM: Ideal Equation>>
•
•
•
•
•
•
•
Set the minimum ON-time or OFF-time 33 µs or more in inputting the PWM signal.
Set the Duty ratio satisfying the condition above.
The recommended PWM signal frequency is from 100 Hz to 10 kHz. There is a possibility to arise the
audible frequency in mounting to the board because it is within the auditory area.
To reduce the fluctuation of input current and increase the accuracy of brightness, the values that C
4.7 (µF) or more , C
When the PWM signal is off, the time to drain C
the actual value is little different from the theoretical value.
Set the amplitude of PWM signal within the range of SHDN terminal specification.
In case dimming by inputting the PWM signal to the SHDN terminal, this IC turns on and off
repeatedly.
And the rush current, which provides the charge to C
condenser.
1 ms (1 kHz) = 100%
Ex) In case PWM Frequency is 1 kHz,
I
F
[mA]
1 kHz is 1 ms (PWM width = 100%) and it takes 10 µs per 1%.
To set the pulse width 33 µs or more, necessary ON-or-OFF-time is calculated below.
Finally, the Duty Ratio can be set in range of 3.3% to 96.7%.
33 µs ÷ 10 µs = 3.3% (Under the condition that 10 µs equals 1%.)
=
325
[mV]
2
RSENS
= 0.1 (µF) or less are recommended.
×
ON
[
Duty
Ω
]
[%]
Set OFF-time
Set ON-time
6
2
of charge depends on the constant number. And so,
2
, arises in turning on. Take care in selecting the
33 µ s or more = 3.3%
Available Duty Ratio
(3.3% to 96.7%)
33 µ s or more = 3.3%
TB62737FUG
2006-06-14
1
=